Protesters in Myanmar on Thursday marked two months since the military seized power by again defying the threat of lethal violence and demonstrating against its toppling of the country’s democratically elected government. Security forces have escalated violence and routinely shot protesters but have been unable to crush the massive public resistance to the Feb. 1 coup. International condemnation and sanctions imposed by Western nations on the military regime have failed to restore peace. In Yangon, the country’s biggest city, a group of young people gathered shortly after sunrise Thursday to sing songs honoring the more than 500 protesters killed so far. They then marched through the streets chanting slogans calling for the fall of the junta, the release of deposed leader Aung San Suu Kyi and the return of democracy. Also read:Myanmar protests continue a day after more than 100 killed Protests were also held in Mandalay and elsewhere. The demonstrations followed a night of violence including police raids and several fires. In Yangon, several retail shops owned in whole or part by Myanma Economic Holdings Ltd., an investment arm of the military, went up in flames. The shops are also targets of boycotts by the protest movement. The crisis in the Southeast Asian nation has expanded sharply in the past week, both in the number of protesters killed and with military airstrikes against the guerrilla forces of the Karen ethnic minority in their homeland along the border with Thailand. The U.N. special envoy for Myanmar warned the country faces the possibility of civil war, a stark reversal for the country that had been progressing slowly toward greater democracy following decades of brutal military rule. In areas controlled by the Karen, more than a dozen civilians have been killed since Saturday and more than 20,000 have been displaced, according to the Free Burma Rangers, a relief agency operating in the area. The U.N. Human Rights Office for Southeast Asia called on countries in the region on Thursday “to protect all people fleeing violence and persecution in the country” and “ensure that refugees and undocumented migrants are not forcibly returned,” U.N. spokesman Stephane Dujarric told reporters at U.N. headquarters in New York. The U.N. Security Council late Thursday strongly condemned the use of violence against peaceful protesters. The press statement was unanimous but weaker than a draft that would have expressed its “readiness to consider further steps,” which could include sanctions. China and Russia, both permanent Council members and both arms suppliers to Myanmar’s military, have generally opposed sanctions. Also read:Protests in Myanmar as junta chief marks Armed Forces Day In addition to the deaths reported by the relief agency, an airstrike on a gold mine in Karen guerrilla territory on Tuesday killed as many as 11 more people, according to a local news outlet and an education worker in touch with residents near the site. Saw Kholo Htoo, the deputy director of the Karen Teacher Working Group, said residents told him five people were killed at the mine and six others at a nearby village. The Bago Weekly Journal also reported the attack. “Our soldiers know how to escape, but the airstrike killed the civilians,” said Saw Thamein Tun, a central executive committee member of the Karen National Union, the leading political body representing the Karen minority. About 3,000 Karen villagers have fled to Thailand in recent days, but many have returned under unclear circumstances. Thai authorities said they went back voluntarily after a brief stay, but aid groups say they are not safe and many remain in hiding in the jungle and in caves on the Myanmar side of the border. An opposition group consisting of elected lawmakers who were not allowed to be sworn into office Feb. 1 has put forth an interim charter to replace Myanmar’s 2008 constitution. By proposing greater autonomy for ethnic minorities, the group’s move could help ally the armed ethnic militias active in border areas with the mass protest movement based in cities and towns. On Thursday, demonstrators in several areas burned copies of the 2008 constitution to celebrate the move by the Committee Representing Pyidaungsu Hluttaw, the country’s legislature, which calls itself the legitimate government. In Mandalay, protesters burned pages under the gaze of Buddhist monks who gave their backing with the three-fingered salute adopted by the resistance. Also read:Funerals become scenes of Myanmar resistance, more violence The 2008 constitution ensured military dominance by reserving it enough seats in the legislature to block any charter changes and by retaining control of key government ministries. In seeking an alliance with ethnic minority armed groups, the ousted lawmakers hope to form a joint army as a counterweight to the government armed forces. More than a dozen ethnic minority groups have sought greater autonomy from the central government for decades, sometimes through armed struggle. Even in times of peace, relations have been strained and cease-fires fragile. Several of the major groups — including the Kachin, the Karen and the Rakhine Arakan Army — have denounced the coup and said they will defend protesters in their territories. Ousted leader Suu Kyi, already charged with four minor criminal offenses, is facing an additional one of violating Myanmar’s colonial-era Official Secrets Act, which is punishable by up to 14 years’ imprisonment, said one of her lawyers, Khin Maung Zaw. He said Suu Kyi and Australian economist Sean Turnell, who served as her adviser and was also detained on the day of the coup, were officially charged on March 25 in a Yangon court. He provided no other details. The junta has announced it is also investigating Suu Kyi for alleged corruption, and has presented video testimony on state television of a business tycoon and a fellow politician accusing her of accepting large amounts of cash and gold. Her supporters dismiss the accusations as politically motivated and aimed at preventing her return to politics. A hearing that Suu Kyi attended by video was held Thursday at a court in the capital, Naypyitaw, to discuss her legal representation.